void _bw_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker bw = sender as BackgroundWorker;
Camera camera = _camera;
// Note: the image is disposed once the camera gets disposed.
// Therefore you should copy the image if needed in another
// thread or make sure the camera is not disposed.
Image <Bgr, byte> img;
while (!bw.CancellationPending)
{
img = camera.Frame();
if (img != null)
{
lock (_lock_event) {
if (_on_frame != null)
{
_on_frame(this, img);
}
}
img.Dispose();
}
_fts.UpdateAndWait();
}
e.Cancel = true;
_stopped.Set();
}
/// <summary>
/// Calculates the transformation matrix, which is used to transform the 3d-object points, which were scanned with reference
/// to the moved marker coordinate system, back to the initial marker system and henceforth back to the camera system.
/// The camera object is needed in order to gain the current camera frame. Furthermore, the cameras' intrinsics are needed
/// to perform an extrinsic calibration. Note, that every kind of pattern can be used.
///
/// The transformation matrix is calculated as follows:
/// * If 'UpdateTransformation' is being called for the first time, an extrinsic calibration is performed in order to find
/// the initial orientation of the used pattern.
/// * If the initial orientation has already been found, the extrinsic calibration is performed again. Afterwards
/// the current orientation is available, represented by the extrinsic matrix.
/// * Form the extrinsic matrix (4x3) (current position) to a homogeneous 4x4 matrix.
/// * The final transformation matrix is calculated as follows: _final = initial * current.Inverse();
/// </summary>
public bool UpdateTransformation(Camera the_cam)
{
Matrix extrinsicM1 = Matrix.Identity(4, 4);
ExtrinsicCameraParameters ecp_pattern = null;
ExtrinsicCalibration ec_pattern = null;
Emgu.CV.Image<Gray, Byte> gray_img = null;
System.Drawing.PointF[] currentImagePoints;
//first call: calculate extrinsics for initial position
if (_firstCallUpdateTransformation == true && _cpattern != null)
{
gray_img = the_cam.Frame().Convert<Gray, Byte>();
//set the patterns property: intrinsic parameters
_cpattern.IntrinsicParameters = the_cam.Intrinsics;
if (_cpattern.FindPattern(gray_img, out currentImagePoints))
{
try
{
//extr. calibration (initial position)
ec_pattern = new ExtrinsicCalibration(_cpattern.ObjectPoints, the_cam.Intrinsics);
ecp_pattern = ec_pattern.Calibrate(currentImagePoints);
if (ecp_pattern != null)
{
_ecp_A = ecp_pattern;
_extrinsicMatrix_A = ExtractExctrinsicMatrix(_ecp_A);
_logger.Info("Initial Position found.");
_firstCallUpdateTransformation = false;
}
}
catch (Exception e)
{
_logger.Warn("Initial Position - Caught Exception: {0}.", e);
_firstCallUpdateTransformation = true;
_ecp_A = null;
return false;
}
}
else
{
_logger.Warn("Pattern not found.");
_firstCallUpdateTransformation = true;
_ecp_A = null;
return false;
}
}
//if initial position and pattern are available - calculate the transformation
if (_ecp_A != null && _cpattern != null)
{
gray_img = the_cam.Frame().Convert<Gray, Byte>();
//try to find composite pattern
if (_cpattern.FindPattern(gray_img, out currentImagePoints))
{
//extrinsic calibration in order to find the current orientation
ec_pattern = new ExtrinsicCalibration(_cpattern.ObjectPoints, the_cam.Intrinsics);
ecp_pattern = ec_pattern.Calibrate(currentImagePoints);
if (ecp_pattern != null)
{
//extract current extrinsic matrix
extrinsicM1 = ExtractExctrinsicMatrix(ecp_pattern);
_logger.Info("UpdateTransformation: Transformation found.");
}
else
{
_logger.Warn("UpdateTransformation: Extrinsics of moved marker system not found.");
return false;
}
}
else
{
_logger.Warn("UpdateTransformation: Pattern not found.");
return false;
}
//now calculate the final transformation matrix
_final = _extrinsicMatrix_A * extrinsicM1.Inverse();
return true;
}
else
{
_logger.Warn("UpdateTransformation: No Pattern has been chosen.");
return false;
}
}
/// <summary>
/// Calculates the transformation matrix, which is used to transform the 3d-object points, which were scanned with reference
/// to the moved marker coordinate system, back to the initial marker system and henceforth back to the camera system.
/// The camera object is needed in order to gain the current camera frame. Furthermore, the cameras' intrinsics are needed
/// to perform an extrinsic calibration. Note, that every kind of pattern can be used.
///
/// The transformation matrix is calculated as follows:
/// * If 'UpdateTransformation' is being called for the first time, an extrinsic calibration is performed in order to find
/// the initial orientation of the used pattern.
/// * If the initial orientation has already been found, the extrinsic calibration is performed again. Afterwards
/// the current orientation is available, represented by the extrinsic matrix.
/// * Form the extrinsic matrix (4x3) (current position) to a homogeneous 4x4 matrix.
/// * The final transformation matrix is calculated as follows: _final = initial * current.Inverse();
/// </summary>
public bool UpdateTransformation(Camera the_cam)
{
Matrix extrinsicM1 = Matrix.Identity(4, 4);
ExtrinsicCameraParameters ecp_pattern = null;
ExtrinsicCalibration ec_pattern = null;
Emgu.CV.Image <Gray, Byte> gray_img = null;
System.Drawing.PointF[] currentImagePoints;
//first call: calculate extrinsics for initial position
if (_firstCallUpdateTransformation == true && _cpattern != null)
{
gray_img = the_cam.Frame().Convert <Gray, Byte>();
//set the patterns property: intrinsic parameters
_cpattern.IntrinsicParameters = the_cam.Intrinsics;
if (_cpattern.FindPattern(gray_img, out currentImagePoints))
{
try
{
//extr. calibration (initial position)
ec_pattern = new ExtrinsicCalibration(_cpattern.ObjectPoints, the_cam.Intrinsics);
ecp_pattern = ec_pattern.Calibrate(currentImagePoints);
if (ecp_pattern != null)
{
_ecp_A = ecp_pattern;
_extrinsicMatrix_A = ExtractExctrinsicMatrix(_ecp_A);
_logger.Info("Initial Position found.");
_firstCallUpdateTransformation = false;
}
}
catch (Exception e)
{
_logger.Warn("Initial Position - Caught Exception: {0}.", e);
_firstCallUpdateTransformation = true;
_ecp_A = null;
return(false);
}
}
else
{
_logger.Warn("Pattern not found.");
_firstCallUpdateTransformation = true;
_ecp_A = null;
return(false);
}
}
//if initial position and pattern are available - calculate the transformation
if (_ecp_A != null && _cpattern != null)
{
gray_img = the_cam.Frame().Convert <Gray, Byte>();
//try to find composite pattern
if (_cpattern.FindPattern(gray_img, out currentImagePoints))
{
//extrinsic calibration in order to find the current orientation
ec_pattern = new ExtrinsicCalibration(_cpattern.ObjectPoints, the_cam.Intrinsics);
ecp_pattern = ec_pattern.Calibrate(currentImagePoints);
if (ecp_pattern != null)
{
//extract current extrinsic matrix
extrinsicM1 = ExtractExctrinsicMatrix(ecp_pattern);
_logger.Info("UpdateTransformation: Transformation found.");
}
else
{
_logger.Warn("UpdateTransformation: Extrinsics of moved marker system not found.");
return(false);
}
}
else
{
_logger.Warn("UpdateTransformation: Pattern not found.");
return(false);
}
//now calculate the final transformation matrix
_final = _extrinsicMatrix_A * extrinsicM1.Inverse();
return(true);
}
else
{
_logger.Warn("UpdateTransformation: No Pattern has been chosen.");
return(false);
}
}
